To provide a two-stage method for producing a lightly colored polyol fatty acid polyester having a high degree of substitution with a fatty acid group.
This two-stage method for producing a polyol fatty acid polyester comprises the first step which is a solvent-based esterifying reaction and the second stage that is a solvent-free esterifying reaction. In the first stage, a polyol in the solvent is reacted with a lower alkyl ester of a fatty acid at a relatively low temperature using an alkaline salt catalyst. When a desired degree of esterification is obtained, the resultant partially esterified polyol fatty acid polyester and the solvent-containing phase are separated. The separated partially esterified polyol fatty acid polyester is further esterified with the same or different fatty acid lower alkyl ester in the second stage with an alkaline salt catalyst using solvent-free high-temperature conditions. Thereby, the degree of substitution is increased. Most of color bodies and other contaminants capable of producing color are removed with the solvent in the first stage and, therefore, are not present during the higher temperature reactional conditions in the second stage.
LESLIE GEORGE WEST
ROBERT CHARLES DINWOODY
RICHARD STEWART SILVER
